Combination agitator and chopper for intake of slurry pump



D. J. GRIBBLE Feb. 25, 1969 COMBINATION AGITATOR AND CHOPPER FOR INTAKEOF SLURRY PUMP Sheet I of 2 Filed Nov. 14. 1966 Donald josep/z Gnfi/e BYINVENTOR Feb. 25, 1969 D. J. GRIBBLE COMBINATION AGiTATOR AND CHOPPERFOR INTAKE OF 'SLURRY PUMP I Sheet i of 2 Filed Nov. 14, 1966 0054/4Jbsepfi Gribble INVENTOR /v United States Patent Ofiice 3,429,513Patented Feb. 25, 1969 3,429,513 COMBINATION AGITATOR AND CHOPPER FORINTAKE F SLURRY PUMP Donald J. Gribble, Windsor, Calif., assignor toAgpro, Inc., Santa Rosa, Calif., a corporation of California Filed Nov.14, 1966, Ser. No. 594,207 US. Cl. 24146 Int. Cl. B02c 18/10, 18/40 6Claims ABSTRACT OF THE DISCLOSURE This invention relates to slurryprocessing apparatus, and more specifically to a slurry agitator andcutter means adapted to operate in conjunction with each other tomaintain the agitator and its drive means free of accumulations ofsolids and to divide solids contained within the slurry.

ln systems wherein a mixture of liquid and solids is processed, suchmixture being otherwise known as a slurry, it is frequently necessary toprovide a storage region for the slurry until it may be used. A slurryrequires circulation or other means of agitation to maintain its solidsin suspension and may need treatment to reduce the size of large solidscontained in the slurry. Agitation may be produced by a propellerrotated through a motor-driven drive shaft, however, difficulties mayarise in the use of such an agitator where the slurry contains solidswhich tend to accumulate on the agitator. This is especially a problemwhere the slurry contains fibrous, stringy, or other flexible materialswhich have a tendency to wrap around a rotating propeller and shaft. Theundesirable accumulation of these materials on the propeller and shaftdecreases the efiiciency of the agitator, and may result in undue wearof the parts within the system.

A general object of this invention is to provide novel means forpreventing the accumulation of solids on a slurry agitator and its drivemeans.

In furtherance of this objective, it is an object to provide apparatusfor handling slurries which comprise the combination of a motor-drivenrotating shaft, an agitator attached to and rotating with the driveshaft, and cutter means adjacent the agitator adapted to maintain boththe agitator and drive shaft free of solid materials which otherwisemight collect thereon.

More particularly, it is an object of this invention to provide novelmeans for maintaining an agitator and its drive shaft free ofcollections of solid materials which includes a cutter element adjacentthe agitator and drive shaft, attached to and rotatable with the shaftand agitator, and a stationary cutter element providing with hefirst-mentioned cutter element a shearing action for cutting up solids.

Often slurry processing systems also incorporate a distribution pumpwith an intake for the pump submerged within the slurry. Where themixture contains solids of appreciable size, damage may occur to thepump if such solids are drawn into it. Screens may be provided at theintake to prevent this, however, such screens are subject to theaccumulation thereon of solids suspended in the slurry which plug thepump intake and reduce the working efiiciency of the system.

A further object of this invention, therefore, is to provide novelcutter means at a slurry distribution pump intake, adapted to reduce thesize of solids suspended in the slurry prior to the slurry entering thepump.

This invention further contemplates the provision of easing structure atthe intake of a slurry distribution pump, with chambers through whichslurry flows to enter the pump, and a check valve controlling flowbetween the chambers permitting flow of slurry toward the pump whileinhibiting reverse flow. This reduces pump priming problems.

The apparatus of this invention is relatively simple in construction,and as a consequence, is inexpensively produced. It provides troublefree organization for preventing the accumulations of solids on a slurryagitator and its drive means, and for simultaneously dividing largesolids within a slurry.

These and other objects and advantages are attained by the invention,and the same is described hereinbelow in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a cross-sectional elevation view of slurry treatment apparatusincluding a storage tank having defined storage chambers therein, apropeller-type agitator, a pump, and motors positioned on a deck abovethe storage tank which drive the pump and agitator;

FIG. 2 is a top plan view of the apparatus shown in FIG. 1, furtherillustrating the storage tank, motors and P p;

FIG. 3 is a side elevation view of the propeller-type agitator andassociated structure shown in FIG. 1, drawn on a slightly larger scaleand with portions of a casing in the structure broken away;

FIG. 4 is a view taken along the line 44 in FIG. 3, showing in plan oneof a pair of cutter elements provided in the structure; and

FIG. 5 is a view taken along line 55 in FIG. 3, showing in plan apropeller in the agitator and another of the pair of cutter elements inthe structure.

Referring now to the drawings and first of all more particularly toFIGS. 1 and 2, at 10 is shown generally a storage tank in which may bestored a mixture of liquids and solids, also referred to herein as aslurry.

Tank 10 includes the usual side walls, such as the ones shown at 12, anda floor made up of sloping floor portions 14, 16, and 18. Covering thetop of the tank is a platform 20 and decking 22.

The interior of the tank is divided into at least a pair of chambers,shown at 24 and 26, by a pair of vertical Walls 28 and 30. Wall 28 whichmay be a concrete wall extends between the sides of the tank butterminates short of these sides to provide a flow path for slurry aroundthe ends of the wall. Wall 30, which is generally at right angles towall 28 and is shown joining the left end of the wall in FIGS. 1 and 2,is formed from a series of planks 32 fastened to uprights 34. Chamber 24extends to the right of wall 30 in FIG. 1 and is bounded along its baseby floor portion 18. Chamber 26 extends to the left of wall 30 andthence to the far side of wall 28 in FIG. 1 and is bounded by floorportions 14, 16.

Mounted on platform 20 above the storage tank is a pump 40 utilized inwithdrawing slurry from the tank. The pump is driven by energizing amotor 42 which has its output shaft 44 connected by belts 46 to pumpshaft 48. Fluid is exhausted from the pump through discharge conduit 50.The slurry is supplied the pump intake 52 through an elongated conduit54 which extends downwardly into the storage tank and which has itsupper end connected by pipe structure 56 to the pump intake.

Adjacent the base of the storage tank is a propellertype agitator,generally shown at 58, which, as will become more fully apparent, isoperated to produce circulation of the slurry and, through suchcirculation, slurry agitation. The agitator is rotated under powerthrough a power-driven drive shaft 60 which extends downwardly into thestorage tank through a pipe 62. Drive shaft 60 is rotated under power byenergizing a motor 64 mounted on the platform adjacent motor 42.Connecting the output shaft 66 of motor 64 and the upper end of driveshaft 60 are belts 68 trained over suitable pulleys secured to theoutput shaft and drive shaft respectively.

As is best seen in FIG. 1, the propeller-type agitator is mounted withinthe confines of a cylindrical shroud or duct 70. Such shroud, which isopen at opposite ends, is supported adjacent the base of the tank on aplatform 72 which extends between the base of wall and the left marginof floor portion 18 in FIG. 1. The interior of shroud 70 provides a flowpath for slurry from chamber 26 through the shroud into chamber 24.

Referring now more particularly to FIGS. 3, 4, and 5, suitably fastenedto the base of pipe 62, which encases drive shaft 60, and conduit 54,providing for the feed of slurry to the pump, is casing structure 76.This includes a substantially cylindrical portion 76a concentric withconduit 54 and a substantially cylindrical portion 76b concentric withpipe 62. Casing wall 80 closing off a part of cylindrical portion 76b isprovided with an opening, shown at 82, permitting slurry within thechamber defined within cylindrical portion 76b to pass into the chamberdefined within the interior of cylindrical portion 76a. A check valve,more specifically a flapper valve 84, hinged to the casing structure at86 swings upwardly to the position shown in FIG. 3 to accommodate slurryflow upwardly into the latter of these two chambers. Slurry flow in thereverse direction, however, is inhibited by the valve droppingdownwardly to close off opening 82.

Propeller-type agitator 58 comprises a propeller 90 which isnonrotatably secured to the base of drive shaft 60 through suitablysecuring the hub 92 of the propeller to an end portion of the driveshaft protruding below casing structure 76. As contemplated herein, withoperation of the agitator the slurry is simultaneously subjected to achopping action effective to divide solids in the slurry, wherebyentanglement of solid material on the drive shaft is inhibited and thematerial supplied the pump is in such form as to be easily handled bythe pump.

To this end it will be noted that secured to shaft 60 directly adjacentpropeller 90 is an elongated cutter element, more specifically a bar,shown at 94. Shaft 60 extends through the bar at a point located midwaybetween its ends. Each longitudinal edge of the bar is sharpened as bybeveling the edge on the underside of the bar along its length. The barfits within a suitably recessed region extending along the trailingedges of the agitator propeller so that the top face of the bar is flushwith the trailing edges where such edges extend outwardly on thepropeller blades from the ends of the bar.

Superimposed over bar 94 is another cutter element comprising what isreferred to herein as shear plate 96. Such shear plate includes anannnular expanse 96a encircling the drive shaft, and integral with thisexpanse arms 96b, which extend radially of shaft 60. Projectingoutwardly from the annular expanse, at approximately the location of thearms, are projections 960. The shear plate rests on bar 94, andprojections 960 are received within notches 98 formed in the casingstructure, with the shear plate in this manner prevented from rotatingwith rotation of shaft 60.

Mounted on wall 80 of the casing structure above expanse 96a atapproximately the point where each arm 96b joins with the expanse is atravel limiting stud 100. In FIG. 3 only two of such studs are shown asthe other one has been removed from the drawing. These studs limit theupward travel permitted the shear plate with respect to bar 94, andobviously with adjustments made in the position of these studs theamount of free travel permitted the shear plate may be changed.

Describing now how the apparatus described may be operated to produceagitation of the slurry and chopping up of solids in the slurry, motor64 is operated to produce rotation of drive shaft and the propeller-typeagitator which is at the base of the shaft. With rotation of theagitator, slurry (which typically might be at the level indicated at102) is caused to circulate within the tank with such passing fromchamber 26 and through shroud into chamber 24, thence to return tochamber 26 by flowing around the right end of wall 28 in FIG. 1. Withsuch circulation solids in the slurry tend to be maintained insuspension. When it is desired to remove slurry from the tank, pump 40which constitutes a distribution pump in the apparatus is operatedthrough energizing of motor 42. With energizing of the pump a lowpressure condition results in conduit 54 and slurry is drawn into theconduit through casing structure 76, with such slurry then traveling topump intake 52. Valve 84 opens to accommodate slurry fiow throughaperture or opening 82. Slurry on flowing into the casing structurepasses through openings defined in the shear plate between the arms 96bof the shear plate. Solids in such slurry are subjected to a shearingaction as the ends of bar 94 move in repeated shearing strokes acrossthe lower faces of arms 96b.

To stop the distribution of slurry the pump is stopped. Valve 84 closesto hold a column of the slurry in conduit 54. Slurry fiow into thecasing structure stops. The propeller-type agitator then functions onlyto produce circulation within the storage tank.

The apparatus of the invention has been found to constitute a practicalanswer to the problem involved in handling slurry which otherwise wouldtend to produce fouling of the propeller-type agitator and damage to thepump if permitted to flow into the pump.

While an embodiment of the invention has been described, variations andmodifications are possible without departing from the invention. It isdesired to cover all such modifications as would be apparent to oneskilled in the art, and that come within the scope of the appendedclaims.

It is claimed and desired to secure by Letters Patent:

1. Slurry processing apparatus comprising a powerdriven rotatable shaft,an agitator mounted on said shaft for rotation with the shaft andoperable on such rotation to produce a flow of slurry in a pathextending along the shaft toward one end of the shaft, cutter meansincluding a cutter element mounted on said shaft toward said one end ofthe shaft from the agitator in the flow path of said slurry movable withthe shaft, operable on movement to divide solids in the slurry, casingstructure mounted adjacent said cutter means defining a chamberreceiving slurry flowing in said path and past the cutter means, andconduit means connecting with said chamber for channeling slur-ry fromsaid chamber.

2. The apparatus of claim 1, wherein said cutter means further comprisesa shear plate which encircles the shaft and said shear plate hasspaced-apart cutter arms extending radially outwardly from the shaft,each of said arms including a cutting edge, said cutter element movingin a shearing stroke over said cutting edges on rotation of said shaft.

3. The apparatus of claim 1 which further comprises a pump for pumpingthe slurry, and wherein the intake of said pump is connected to saidconduit means to be supplied slurry through said conduit means.

4. Slurry processing apparatus comprising a duct, 9. power-drivenrotatable shaft and a propeller mounted on said shaft for rotation withthe shaft, said propeller on rotation of the shaft producing a flow ofslurry in a path extending through the duct in a direction generallyparalleling the axis of the shaft, casing structure spaced along theaxis of said shaft from said propeller and inwardly of the sides of theduct whereby a passage is provided for slurry flow through the duct andaround the outside of the casing structure, said casing structuredefining a chamher for receiving a portion only of the slurry flowing insaid path through said duct, cutter means including a cutting elementmounted on said shaft adjacent the propeller operable on rotation of theshaft to divide solids in the slurry received in said chamber, andconduit means connecting with said chamber for channeling slurry fromsaid chamber.

5. The apparatus of claim 4, wherein the propeller is mounted on one endof the shaft and the flow of slurry produced by the propeller is fromsaid one end toward the shafts opposite end, the casing structureencircles the shaft and is located toward the shafts opposite end fromthe shafts said one end, and said cutter means is located toward thecasing structure from the propeller.

a pump for pumping slurry, and wherein the intake of said pump isconnected to said conduit means to be supplied slurry by the conduitmeans.

References Cited UNITED STATES PATENTS 357,686 2/1887 Nacke 241-461,763,379 6/1930 Thurm et a1 24198 2,485,368 10/1949 Dodge 241463,318,248 5/1967 Rembold 241-46 GERALD A. DOST, Primary Examiner.

US. Cl. X.R.

6. The apparatus of claim 4 which further comprises 15 257

